Research Projects
Submarine:
Part of my research, well actually much of my recent focus, has been on understanding eruption processes on the seafloor. To do this I have had to rely on colleagues with access to a ship and submarines. It is very different to field work on land, apart from having ready access to ice cream at any moment, a real bed and somebody that cooks for you, it can be really fun. I have spent most of my sea time with the Monterey Bay Aquarium Research Institute (MBARI), which operates the R/V Western Flyer and ROV Doc Ricketts. You can see Doc Ricketts being deployed through the moon pool aboard the Western Flyer and its 5 exceptional pilots in the adjacent photos.
Studying large scale marine density currents generated by pyroclastic eruptions produced on Honga Tonga-Hunga Ha'apai Volcano
In 2022, Hunga Tonga volcano erupted explosively producing a widely studied stratospheric ash cloud and an estimated 10 cubic kilometers of much less well studied submarine volcaniclastic deposits. This project seeks to characterize the large-scale submarine volcaniclastic density currents produced by this eruption. Systematic sampling and mapping in a at-sea field campaign using remotely operated vehicles, and ship-based coring equipment will sample the eruption deposits at multiple spatial scales.
This project will work closely with other graduate students and involve international and regional travel. Extensive collaboration is planned, with scientists from Tonga, New Zealand, Australia and the US. Students will go to sea and participate in lab work in various labs, including the Smithsonian, around the US. Interested students should contact ryan.portner@sjsu.edu.
Photo from Tonga Geological Services
Is volcanism on the Arctic mid-ocean ridge system linked to climatic fluctuations through the last major glacial cycle?
Sediment cores from the Arctic mid-ocean ridge system will help address a working hypothesis that lower sea level during the last glacial period triggered more voluminous and explosive eruptions on the deep seafloor. This project will support a student's travel to Svalbard, Norway where they will join a cruise to the Arctic Ocean and subsequently work on sediment cores in Bergen, Norway. Cores will be scanned and subsampled for additional work including: granulometry, componentry and geochemistry.
West Mata Volcano: Lau Back Arc Basin - Southwest Pacific Ocean, Tonga
Being the site of the deepest eruption ever videotaped, West Mata has been a game changer in the minds of submarine volcanologists. Without explaining the details check out the video footage collected from cruises to West Mata in 2009....... Video is courtesy of the National Science Foundation (NSF) and National Oceanic and Atmospheric Association (NOAA).
My students and I will be working on samples from the eruption shown in the video. There are also plans to expand this project with colleagues from the University of Hawaii and Tasmania to include new samples from subsequent eruptions collected since 2009.
Bubbles-with_sound_ngeo1275-s6.wmvAxial Seamount: Juan de Fuca Ridge - offshore Pacific Northwest, USA
Located ~500 nautical miles due west of Portland Oregon, Axial Seamount occurs at the heart of the Juan de Fuca Ridge. It is the surface expression of the 1800 km long Cobb hot-spot chain which extends northwest to Alaska. There has been much research on Axial Seamount over the last several years and it is the site of the first cabled observatory on an active submarine volcano.
Ongoing work on samples recovered by sediment push cores will provide a detailed historical record of eruptions on Axial Seamount and their impact on the local biologic communities and oceanographic system.
Alarcon Rise: Northern EPR Gulf of California Southern Baja, Mexico
Located in the mouth of the Gulf of California, Alarcon Rise forms the northernmost segment of the East Pacific Rise mid-ocean ridge and the southernmost segment of the Gulf of California rift basin. This location puts Alarcon Rise within a transition zone between oceanic seafloor-spreading and oblique continental-rifting.
Two expeditions to Alarcon in 2012 and 2015 collected samples of a one-of-a-kind mid-ocean ridge rhyolite lava dome at a depth of 2350 meters below sea level (mbsl). Using seafloor samples and accompanying high resolution seafloor maps this projects seeks to understand the formation and eruption of rhyolite on the deep-mid ocean ridge. High resolution bathymetry of the entire Rise is shown in the adjacent video feed (Date from MBARI). Can you find the rhyolite dome?
Alarcon_3D_flyby_Final_II.f4vSubaerial:
The other side of my research involves getting into the mountains and looking at ancient analouges to the more more marine projects outlined above. I am also interested in the basin record of tectonic uplift, metamorphism and magmatism as preserved by sedimentary and volcanic rocks.
Coast Range Ophiolite: Northern California, USA
The coastal mountains of California locally expose some pristine remnants of obducted oceanic crust. One such example occurs north of San Francisco where 2 projects are waiting to be worked on. The first project will investigate volcanic deposits with physical characteristics akin to what we see on Axial Seamount (see above). This project will likely take advantage of similar localities further north in Oregon and British Columbia. The second project will entail mapping, stratigraphy and petrology of rare sedimentary deposits containing a deeper crustal provenance. Such ophiolitic sediments are rare, but give clues to the tectonic origin of the Coast Range Ophiolite.
Sediment provenance associated with exhumation of the Snake Range metamorphic core complex
This study, set in east-central Nevada, will investigate the utility of cold Cathodoluminescence in provenance studies of minerals derived from the highly attenuated footwall and more brittley deformed hangingwall of the Snake Range metamorphic core complex. The project involves field and lab work and will also study the relationship between volcanism, tectonism and sedimentation associated with Eocene-Miocene extension in the greater Basin and Range.
